Trip control mechanism



Sept. 28, 1954 F. A. HASSMAN 2,690,097 TRIP CONTROL MECHANISM Filed July 11, 1952 3 Sheets-Sheet l M In. 5 E: 3/ 70 INVENTOR.

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TRIP CONTROL MECHANISM Filed July 11, 1952 3 Sheets-Sheet 2 INVENTOR. FRI D 11. HA SSH/1N BY j A mrwm fl lfgk Sept. 28, 1954 F. A. HASSMAN 2,690,097 TRIP CONTROL MECHANISM Filed July 11, 1952 3 Sheets-Sheet 3 Fi .5 72 Bi .7

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Patented Sept. 28, 1954 UNETED STATES PATENT OFFICE 2,690,097 TRIP CONTROL MECHANISM Fred A. Hassman, Cincinnati, Ohio, assignor to The Cincinnati Milling Machine 00., Cincinnati, Ohio, a

Application July 11, 1952,

Claims.

the mechanism shown in the patent, it becomes impossible when the table cycle is stopped automatically in the midst of its travel in a given direction to restart movement of the table in the same direction. Therefore, another object of this mediate stop during cyclic travel of the table in a given direction may be obtained without looking up the parts so that the operator may restart the cycle movement in the same direction.

A further object of this invention is to increase the utility of said mechanism by making new within the scope of the appended claims, Without departing from vention.

Referring to the drawings in which like reference numerals indicate like or similar parts:

Figure l is a front elevation of a portion of a milling machine table and its support showing the relationship of the trip elements of this invention.

Figure 2 is of Figure 1.

Figure 3 is a horizontal of Figure 2 showing the table reversing clutch and actuating mechanism therefor.

Figure 4 is a section on the line 4-4 of Figure 2 showing the two position detent mechanism.

Figure 5 is a section on a vertical section on the line 2-2 section on the line 33 are views showing different rotatable positions of the trip plunger as the table progresses in its movement.

Figure 11 is a diagrammatic transmission mechanism.

corporation of Ohio Serial No. 298,304

view of the table Figure 12 is a view of reversing.

Figure 13 is a of Figure 6.

This invention deals broadly with automatic cyclic control of a movable slide of a machine tool, such as the table of a milling machine shown in the patent supra, which is driven by a transmission which briefly may be described as a feed-rapid traverse transmission.

For a clearer understanding of the invention it is desired to point out that in the disclosure of a prior art dog used for detail section on the line l3|3 numeral H indicates the rate determining clutch. Power for drivin the table through these clutches is derived from a which supports a traverse drive gear, and adapted to be connected to the shaft I2 by the shifting of clutch ll and a gear l4 secured to the shaft I2 and known as the feed drive gear. The gear l4 drives, through a variable feed transmission I5 of any suitable type, an output feed shaft is that is connected through an overrunning clutch H to a gear I 8. Thus, the gear i8 is constantly driven in one direction at all times by the shaft I2. However, when the clutch II is engaged, the gear I8 is driven at a faster rate by the rapid traverse gear i3 24 intermeshes with bevel gears 21 and 28 supported co-axially of the screw 25.

The reversing clutch IE! is splined on the screw 25 and has clutch teeth on opposite sides for engagement with corresponding clutch teeth on the opposing faces of the gears ill and 28 whereby engagement with the gear it will drive the screw in one direction, and engagement with the gear 28 will cause the screw to be driven in the opposite direction.

A trip plunger, which acts as the intermediate agent between the trip elements carried by the table 29 slidable on guideways 3d, and the transmission elements, is indicated by the reference numeral 3i as more particularly shown in Figures 1 and 2. The rapid traverse clutch it is operatively connected to the trip plunger through the following mechanism. A piston member .32 in Figure ii is slidably mounted in opposed cylinders 33 and 3 1, and is operatively connected to the clutch member 5 l by a shifter fork 3-5. Thus, by admission of fluid pressure to the cylinder 33 the clutch is disengaged and upon admission of pressure to the cylinder 34 the clutch is engaged. The cylinders and 3d are connected. by chan nels and to ports 3? and 38 respectively of a rapid averse control valve 38. This valve has a pressure port ii) which is supplied through channel M by suitable pump it having a relief valve A valve plunger id is slidably mounted in the valve housing 3.; for alternatively connecting the pressure port Gil to the motor ports 3'! or 32!. The plunger M is operatively connected to rod id by a crank id on the side of rod 36 which, as diagrammatically indicated in Figure 11, is connected by a second. crank 1-1 on the other end of the rod to the trip plunger M. The actual construction is more particularly shown in Figure 4 in which the lug or crank ll on the shifter rod d6 fits in a socket 47: in the periphery of the trip plunger ill whereby a predetermined axial movement of the plunger 3! will cause rotation of the shifter rod it to operate the rapid traverse clutch.

The reversing clutch Ill, as shown in Figure 3, has a shifter fork 48 which is slidably mounted on a shifter rod M which, in turn, is connected by a lever {iii to the trip plunger 3 i. In this case, the lever st is provided with a bifurcated end 5! which embraces a cam member 52 keyed to the trip plunger 31 without lost motion whereby as the trip plunger is rotated the lever will move in unison therewith. At this point it should be pointed out that the both axial and rotatable movement, and it will be noted from Figure 11 that the axial movement causes shifting of the valve plunger M, and from Figure 3 that rotatable movement causes shifting of the reversing clutch.

It is, or course, desirable that suitable detent mechanism be provided for holding the trip plunger in definite positions, and in Figure 5 is shown a three-position detent member 53 which is keyed to the plunger 3! which cooperates with a detent pawl M which is spring actuated by a spring 55 as shown in Figure l. It will now be seen that as the trip plunger is rotated in a clock wise direction as viewed in Figures 3 and 5, that the reversing clutch It will be moved out of engagement with the gear 2?, and when the pawl. rides over the peak 56 it will snap into the notch 5i and thereby disengage the clutch, or, in other words, move it to a neutral or stopposition. Since this will disconnect power from the lead screw, the table will stop and further rotation of the trip plunger will cease. It then becomes necessary for the operator through the medium of the manual control lever 58, which has a ball pivot 59, as shown in Figure 2, to shift the trip plunger is capable of plunger in a desirable direction to reengage the clutch when further movement of the table is desired. The ball pivot is intermediate the length of the manual control lever, and has a ball end 6% which fits in a socket H of the member 62 which is keyed to the plunger 3!. By means of this construction the operator is enabled to rotate the plunger, or move it axially by proper manipulation of the lever 5d. The various positions to which the lever may be moved are shown in Figure 1. The detent member as is provided with another notch 63 which holds the trip plunger in position when the clutch it is shifted into engagement with the gear 2.8.

When the trip plunger is in engagement with either notch 63 or 5 shown in Figure 5, it may be moved axially downward to change the rate of support movement by causing engagement of the rapid traverse clutch H. In so doing, the pawl 54 will slide out of engagement with the notch 64 of detent member 53 and into engagement with a notch 65 in a second detent member 65 attached to the plunger 5|. Or, if the detent pawl M is in engagement with the notch 63 in ber 53 it will slide out of engagement with the notch 63 and into engagement with a second notch El in the member E56. However, when the pawl 5a is in engagement with the notch shown in Figure 5, the trip plunger cannot be moved downward because the pawl 5 will be in interference with the peak 68 located between the notches B5 and 61.

In the construction shown in the pater t concave-shaped dog 69, such as shown in Figur 12, is utilized for engagement with the wing o" the plunger iii to rotate the plunger to a sto position. This type of dog, however, can only h used at the end of a table stroke to move the plunger to a stop position for the following sons. The dog wedges itself under the wing in rotating the wing to the stop position so that it prevents reverse rotation of the wing back to its original position. Thus, after the table has stopped, it is not possible to start it moving again in the same direction. It will thus be seen that an automatic stop can only be effected at the end of a table stroke because at that time the table is reversed anyway.

However, in automatic milling operations where fixtures are spaced on the table and the table reciprocates back and forth to alternately engage work in the respective fixtures, it is common practice for the operator to change the work in one fixture while the cutter is machining the work piece in the other fixture. Under these conditions it is desirable for safety reasons that after the cutter has finished on one work piece and the table has been reversed to move toward the other fixture, that the travel of the table be halted midway between the fixtures to insure that the operator has completed the work changing operation. A dog, such as 69, would be inoperative for this purpose because the table could not be started again in the same direction because of interference with the dog.

By means of this invention, a tripping means has been provided for overcoming this difficulty. Referring to Figure 6, a dog construction is shown comprising an elongated housing, indicated generally by the reference numeral 5i having a rear portion i2 which is made narrow enough to slide into the T slot l3 formed in the front face of the table 29, and a front plate portion M which is made much wider so as to provide for the drilling or holes to receive T bolts it by pressed equalizing tinuously urged by springs 79 to hold the pawl in a normal central position. The plungers are slidable in bores 80 formed in the housing. The pawl 16 has a right angle bend, as shown in Figure 13, by which it extends downward, and at the lower end is provided with a V-shaped extension 8|. The pawl is so proportioned that the V- shape extension lies in line with the wing it of plunger is axi- When the trip is moved axially to its rapid traverse position the wing will be out of line with the trip pawl, and the table will pass by the same without The housing is provided with a shroud or skirt portion 82 which covers and protects the pawl from chips and dirt table and interfere with the opera tion of the trip pawl.

Attention is invited to has a double bevel 83 on Figure 10 adjacent the back wall of the T slot to limit the angle of rotation of the pawl. In opera tion, the trip pawl 16 is secured to the table in the desired longitudinal position thereof, and Figure 6 shows the table and pawl moving to the left with the pawl just engaging the wing it of the fact that the pawl its rear end as shown in tinue to the position shown in Figure 8. At this time the detent 55 shown in Figure has ridden to the top of the peak 56 and is ready to fire as it passes over the peak. The firing operation rotates the trip plunger to the position shown in Figure 9. It should be noted that in so doing the wing cleared the 58, shown in Figures 1 and 2, to rotate the trip plunger back to its original posi- Figure 6, and in so doing, the wing may rotate the pawl in the other direction if there is interference as shown in Figure 10. As the table progresses in its travel, the pawl will return to its normal position automatically by action of the centralizing springs. The operator is traveling in the opposite direction, it being understood that then the wing is angularly positioned clockwise from its position shown in Figure 9 because the reversing clutch is engaged on the other side to efiect the return movement.

ment of new results therewith.

What is claimed is:

1. In a trip control mechanism, the combination with a rotatable trip plunger mounted on a fixed support adjacent to a movable support and having an actuating wing projecting therefrom opposite to the direction of support movement, of means on the movable supportfor engaging and plungers mounted in said housing in engagement with opposite sides of said pawl for centralizing the position of said pawl normal to the direction of support movement, positive stop means for limsaid movable support, rotation of the wing releas ing said pawl for automatic centralization by said spring plungers, whereby the trip plunger may be repositioned to start movement of the support in the same direction without interference between said pawl and said wing.

2. In a trip control mechanism, the combination with a rotatable trip plunger mounted on a fixed support adjacent to a movable support and detents for holding said plunger in a stop position and a running position, said plunger when in a running position having an actuating wing projecting therefrom opposite to the direction of support movement,

ference between said wing and pawl.

3. In a trip control mechanism for a machine tation by the detent mechanism releasing said pawl whereby irecentralization of said pawl by said resilient means will remove said pawl from the path of said wing permitting repositioning of the plunger in its running position.

a. A. trip control mechanism for automatically disengaging the driving clutch of a machine tool support comprising a trip element stationed by said movable support and operatively connected to said clutch, an oscillatable trip pawl mounted on the support for movement therewith, said trip element having a wing projecting therefrom in a direction opposite to the direction of support n'zoveinent and lying in the path of said pawl, said trip pawl in its normal position having a limited amount of lost motion upon engagement with said wing before effecting rotation thereof, detent mechanism associated with said trip element for continuing rotation thereof to a predetermined position to effect disengagement of said clutch whereby completion of said rotation will release said pawl, resilient means for returning said pawl to its normal position whereby said trip plunger may be repositioned to effect engagement of said clutch without interference between said wing and said pawl, and manual means for rotating said trip element.

5. A trip mechanism for controlling movement of a machine table relative to its support, combining a rotatable trip element stationed on said support, a tripping means for the trip element carried by the table, a clutch mechanism engageable by rotation of the trip element in one direction to cause movement of the table, said trip element having a laterally extending wing positionable in the path of said tripping means and extending in a direction opposite to the direction of support movement, said tripping means including a trip pawl having lost motion oscillation, resilient means on opposite sides of said pawl holding said pawl normal to the axis of table movement to engage said wing whereby movement of said table will cause said lost motion to be taken up and said trip element rotated, detent mechanism for completing rotation of said trip element to automatically disengage said clutch mechanism, said resilient means automati cally acting to return said pawl to its normal position whereby reverse rotation of said trip element may be effected to engage said clutch without interference between said pawl and said wing.

References Cited in the file of this patent UNITED STATES PATENTS 

